The prior art discloses heat treatments wherein ammonia and methane combusted with air are mixed together in a furnace to provide heat treating atmospheres. However, this differs from the subject use of dissociated ammonia because in the prior art processes the ammonia is dissociated in the furnace whereas in the subject method the ammonia must be dissociated prior to its introduction into the furnace or other heat treating environment. In the prior art, dissociation of the ammonia in the furnace provides nascent nitrogen which nitrides the workpiece undergoing treatment whereas in the subject method dissociation prior to introduction to the furnace provides molecular N.sub.2 which is inert and does not effect the workpiece undergoing treatment.